No, not weird. Vets have been prescribing pumpkin for dogs and cats for a long time for the fiber it provides. Some cats I've had will eat it plain. You could probably use any type of winter squash that you can grow easily. I've grown Sugar Pie in the past(very meaty), but it gets to a couple of pounds so you have to use a sling to keep the fruit from dropping or pulling the stem down. I don't know if there are smaller punks with thick flesh. I would think you could grow something like acorn squash that has a more bush-like growth if you don't want to trellis.
Apparently there are a number of squashes that are commercially canned...

Here is a link that might be useful: canned pumpkin info

Thanks for your response. The German Shepherd I had before had the same problem, but pumpkin was never prescribed and we had to have his anal glans removed so this was the first I've heard of it.

Yes, I think my Sig would eat it plain. He is hesitant at eating his dogfood when pumpkin isn't in it. I had heard commercial canned pumpkin was made from squash other than pumpkin, but never went any farther into it since I just used it for pies every so often. I do grow different types of squash and this year there will be extra. I have a very large garden that is pretty much full so I thought I'd trellis some things on the fence surrounding it.

I've been wanting to grow pumpkin for my cats after I heard of pumpkins and squash being fed to cats.

The rumor is that Libbys uses Dickinson pumpkin. Squash and pumpkin taste so much alike I'm not surprised that canned 'pumpkin' is really squash. I once had a pie made with canned squash, now I'm wondering what kind of squash it was. It's all pretty good.

A can of pumpkin will last quite a while for my cats. I drop spoonfuls on waxed paper lined cookie sheets and freeze them. When the little disks are frozen, I put them in a ziplock freezer bag. Whenever one of the cats needs a little "help", I thaw a disk and mix it in with some canned food for a few days. Some cats don't like it, but many do, and those that do will often like cantaloupe as well(even though they can't taste sweetness). Maybe it has something to do with the beta-carotene.